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Old 5th October 2012, 12:01   #1
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Default Problem with the accelerator pedal

We were returning last evening in my sister's Figo, my dad's driver was driving.

On top of a railway flyover the guy says "pedal is not working" - he put the car in neutral and kept pumping the pedal - nothing happened.

We just decided to come down the flyover and try again (car was moving all the while, and downward slope was enough to get it down).


Once we reached the ground pedal started working normally !



I came home asked my sister whether this has happened before - she told me it has been happening for a few months now, and every time dealer tells him "pani chala gaya hoga pedal mein" (may be water seeped in the pedal)


Has anyone else encountered this in Figo or any other car?



I'm really worried, my sister travels late in the evening and over very long distances, so if the pedal refuses to work she may get stranded. Plus Toyota's killing-cars were eventually diagnosed with TPS - what if her Figo decides to accelerate suddenly with no respite !
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Old 5th October 2012, 12:24   #2
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Default Re: HELP - Problem with accelerator pedal

Given info points to faulty Accelerator pedal position sensor. it could even be dust problem too ? By the way was there check engine light or error ?
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Old 5th October 2012, 12:40   #3
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Default Re: HELP - Problem with accelerator pedal

Quote:
Originally Posted by v&v View Post
Given info points to faulty Accelerator pedal position sensor. it could even be dust problem too ? By the way was there check engine light or error ?

I thought about TPS sensor, but most of the are magnetic as far as I know (may be I know wrong), so dust should not be a problem. Also it happens very infrequently - hardly replicable right now.

Engine light etc. were all fine, nothing exceptional. The driver just put the car in neutral, let it roll downwards on the flyover till we reached the bottom and tried again - and we heard the "vroom" of the engine - engaged the gear and it worked fine.



I spent some time searching the internet and found nothing at all on this.
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Old 5th October 2012, 12:56   #4
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Default Re: HELP - Problem with accelerator pedal

I too had a similar problem in my safari. It didnt respond at all. Switched off and started again it every thing normal. Later i spoke to TASS they told it mostly due to dust.
Touch wood it never returned again.

TPS is controlled by ECM based on Pedal sensor input and in pedal position sensor AFIAK there are 2 sensor units gives the input to ECM.

I too searched to this problem when it occurred to my car. Let me see if i can share the link for that article.
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Old 5th October 2012, 14:26   #5
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Default Re: HELP - Problem with accelerator pedal

Its the Fly-by-wire pedal sensors, a blow of air will keep them dust free.
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Old 5th October 2012, 15:10   #6
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Default Re: Problem with the accelerator pedal

Here is the link which covers in detail about the same

http://articles.d-tips.com/art8.html

http://www.aa1car.com/library/throttle-by-wire.htm
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Old 5th October 2012, 15:20   #7
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Default Re: Problem with the accelerator pedal

If it's drive by wire, the potentiometer has gone bad, or the wiring might be corroded/frayed. Check on the TB side and the pedal side.

If it's cable type, make sure the cable is held tightly at all points in the engine bay. An insecurely mounted cable will not transfer all the force to the throttle rotor; instead, the cable will move about.


The TPS is fine. If the TPS had a problem,
1) You'd get a Check engine light as it is one of the critical sensors used to calculate fuel injection values (TPS, MAP/MAF, O2, etc) in a speed density based fuelling setup.
2) The engine would respond sluggishly. But it would respond.

Last edited by pranavt : 5th October 2012 at 15:23.
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Old 5th October 2012, 15:31   #8
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Default Re: Problem with the accelerator pedal

If this error occurs frequently, get your ECU logged diagnostic errors checked and also the sensors for sure. The sensors are semiconductors and are tend to behave non-linearly. Such predictive failures cannot be taken for granted as it is driven. Please get it thoroughly checked from a well known service centre.
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Old 5th October 2012, 16:56   #9
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Default Re: Problem with the accelerator pedal

Quote:
Originally Posted by v&v View Post

Thanks for the articles, however I didn't understand much of either of those two. There is a wikipedia article on Throttle position sensors (http://en.wikipedia.org/wiki/Throttle_position_sensor), and there is another "wiki" page (though not wikipedia) http://wiki.seloc.org/a/Throttle_Position_Sensor which gives more info on common TPS faults - my problem is not listed, though it may be an uncommon problem.


Quote:
Originally Posted by pranavt View Post
If it's drive by wire, the potentiometer has gone bad, or the wiring might be corroded/frayed. Check on the TB side and the pedal side.
Are the sensors potentiometer type any more? I thought they are using hall-effect sensors now. But I may be wrog of course.

Quote:
Originally Posted by pranavt View Post
If it's cable type, make sure the cable is held tightly at all points in the engine bay. An insecurely mounted cable will not transfer all the force to the throttle rotor; instead, the cable will move about.

didn't understand this at all

Quote:
Originally Posted by pranavt View Post
The TPS is fine. If the TPS had a problem,
1) You'd get a Check engine light as it is one of the critical sensors used to calculate fuel injection values (TPS, MAP/MAF, O2, etc) in a speed density based fuelling setup.
2) The engine would respond sluggishly. But it would respond.

I suspect the same. There was no response at all - even with a mild response when the car is in neutral the engine should sound running at higher rpm - nothing of the sort happened. I didn't check tacho as I was in the rear seat.

However the explanations my sister has been offered (dust, water ...) don't make sense either.

Quote:
Originally Posted by yogeshnaik View Post
If this error occurs frequently, get your ECU logged diagnostic errors checked and also the sensors for sure. The sensors are semiconductors and are tend to behave non-linearly. Such predictive failures cannot be taken for granted as it is driven. Please get it thoroughly checked from a well known service centre.

My sister told me she has tried twice with the Ford service guys, each time they tell her "madam everything is fine". I told her to give it in writing this time. Her's is an April 2010 Figo and will be out of extended warranty soon. Unless she gets it in writing they may refuse warranty repairs later.

Any pointers on how to deal with the service guys regarding this problem
?
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Old 5th October 2012, 17:07   #10
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Default Re: Problem with the accelerator pedal

Quote:
Originally Posted by vina View Post
My sister told me she has tried twice with the Ford service guys, each time they tell her "madam everything is fine". I told her to give it in writing this time. Her's is an April 2010 Figo and will be out of extended warranty soon. Unless she gets it in writing they may refuse warranty repairs later.

Any pointers on how to deal with the service guys regarding this problem
?
Only one solution. Ask her to take along a Male Family member/ male friend who knows something about cars. Mechanics or service advisors usually take it easy when it is a lady complaining because they assume that they know more than women. No offence, but this is how they think.
I have faced this with my sister and her santro, when I went over and rattled a few automotive jargons, they got more serious and diagnosed and rectified the fault..
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Old 5th October 2012, 19:03   #11
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Default Re: Problem with the accelerator pedal

Quote:
Originally Posted by vina View Post
didn't understand this at all
Vina, In cable type, if there is slack, then all the effort given by the foot on the pedal will not be translated in the TB side.

Regarding your question, if there is absolutely no error from the engine side, then its an error from the pedal side. Also, any errors, however small will be stored in the ECU. I'd advice pluggin in an OBD reader and check if there was any error at all.
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Old 5th October 2012, 20:47   #12
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Default Re: Problem with the accelerator pedal

If it is a drive by wire unit, rapidly pressing and releasing the accelerator pedal may clean up the contacts if there is any dirt causing loss of contact. Also, if the system is drive by wire, the issue is much serious than just a dirty contact or water entering the system, as the accelarator pedal has two potentiometers, a master and slave to achieve fail safe operation. So if the entire pedal becomes dead, then I suspect it to be an ECU input problem. Here is an extract from the manual of an Electric Accl. pedal assembly:

Quote:
In the system, as the throttle position sensor and APP sensor have 2 sensors (main and sub) each, highly accurate
and highly reliable control and abnormality detection are assured.

Last edited by audioholic : 5th October 2012 at 21:04.
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Old 5th October 2012, 20:57   #13
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Default Re: Problem with the accelerator pedal

Quote:
Originally Posted by dhanushs View Post
Vina, In cable type, if there is slack, then all the effort given by the foot on the pedal will not be translated in the TB side.

Regarding your question, if there is absolutely no error from the engine side, then its an error from the pedal side. Also, any errors, however small will be stored in the ECU. I'd advice pluggin in an OBD reader and check if there was any error at all.

Nice to see you after a long time.

If there is any slack in the cable then why would this happen just once in a while? Also why would you need a cable, why not just put the sensor directly at the pedal (may be issues related to optimal position for TPS?)


I don't have an OBD reader and unfortunately I wouldn't be in Delhi when my sister takes it to the workshop. I will try to tell her what to do, but she doesn't understand electronics at all, it will take a few hours just to explain what is ECU.



By the way, I noticed another thing just 30min. ago. In my Figo the Engine Immobolizer light flickers once every 5-6 seconds or so when the car is locked. In her Figo right now it is flickering every second, if not faster ! I noticed when I took my daughter for a walk.

I will tell her to at the very least get her firmware reset/ugraded to GD version. The problem may be related to the Figo turning off problem in some way and may be the Firmware change can help.


By the way @Dhanush - would you know whether Figo/Ikon/Fiesta TPS is Hall effect type or potentiometer type?
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Old 5th October 2012, 23:07   #14
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Default

I had a similar problem with my civic when it was new. Pressing the accelerator wouldn't give any result for a minute and then after pumping it a few times it would slowly receive some signal and then after 5 mins it would function as if nothing had happened.

It used to happen only during rainy season. Linkway Honda tried their best to repair it a few times in the first two years. Every time their answer was 'it is rectified' to resurface another time.

After two years it mysterious disappeared and hasn't appeared again.
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Old 6th October 2012, 19:31   #15
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Default Re: Problem with the accelerator pedal

Quote:
Originally Posted by vina View Post
My sister told me she has tried twice with the Ford service guys, each time they tell her "madam everything is fine". I told her to give it in writing this time. Her's is an April 2010 Figo and will be out of extended warranty soon. Unless she gets it in writing they may refuse warranty repairs later.

Any pointers on how to deal with the service guys regarding this problem?
Every State has Zonal Managers and Quality Engineers. Did you try at the Ford's Customer Care Centre and get the direct contacts emails & phone number of the Engineers? They take such matters very seriously and mail them this link as the BHP community is watching their move. Keep Team-BHP posted.

Last edited by yogeshnaik : 6th October 2012 at 19:34.
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